1. Field of the Invention
The present invention relates to a system for carrying a charge, such as a slab, a billet or a bloom through a reheating furnace, and more particularly a walking-beam furnace, the system comprising at least one tubular support carrying a coolant and at least one rider resistant to high temperature arranged on the tubular support.
2. Prior Art
Known systems for carrying a charge through a reheating furnace, as described in European patent No. EP 0 184 021 B1 which corresponds to U.S. Pat. No. 4,689,009, feature riders which are castings resistant to high temperatures. Such castings may be exposed to temperatures of up to approximately 1,200.degree. C. They have excellent strength properties up to the temperature, but at a temperature above 1,200.degree. C. their strength properties are no longer sufficient for usual applications. Charges, such as in particular slabs or similar products to be reheated for rolling, may on the other hand be reheated to a temperature which is 50.degree. C. to 100.degree. C. higher than the temperature to which known castings may be exposed. Since known riders must be kept at a temperature below the limit temperature to which castings may be exposed, the temperature difference produces necessarily marks in the charge commonly referred to as skid marks. The skid marks represent low-temperature areas which affect final product quality., since they cause differences in thickness and width as well as in product microstructure unless relatively complicated action is taken to remove the skid marks prior to rolling. The importance of the disadvantages associated with the skid marks is increasing, as product quality specifications become increasingly stringent.